Re: [PATCH v4 3/7] staging: vchiq_core: Factor out bulk transfer for blocking mode

[Stefan Wahren]

Hi Umang,

Am 06.09.24 um 09:25 schrieb Umang Jain:
> Factor out bulk transfer for blocking mode into a separate dedicated
> function bulk_xfer_blocking_interruptible(). It is suffixed by
> "_interruptible" to denote that it can be interrupted and -EAGAIN
> can be returned. It would be up to the users of the function to retry
> the call in those cases.
>
> Adjust the calls to vchiq-dev.c ioctl interface and vchiq_arm.c
> for blocking bulk transfers.
>
> Signed-off-by: Umang Jain <umang.jain@xxxxxxxxxxxxxxxx>
i applied this series on top of recent linux-next and the vchiq ping
test on Raspberry Pi 3 B Plus (multi_v7_defconfig) crashes or hanges
strangly.

I bisected the issue to this patch, but it's possible the root cause
might be introduced before.

But i'm pretty sure that the series introduced the regression.

Sorry, i don't have the time analyse this issue deeper.

Best regards
> ---
>   .../interface/vchiq_arm/vchiq_arm.c           |  5 +--
>   .../interface/vchiq_arm/vchiq_core.c          | 42 ++++++++++++++++---
>   .../interface/vchiq_arm/vchiq_core.h          |  5 +++
>   .../interface/vchiq_arm/vchiq_dev.c           |  6 +++
>   4 files changed, 49 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
> index c4d97dbf6ba8..688c9b1be868 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
> @@ -968,9 +968,8 @@ vchiq_blocking_bulk_transfer(struct vchiq_instance *instance, unsigned int handl
>   			return -ENOMEM;
>   	}
>
> -	ret = vchiq_bulk_transfer(instance, handle, data, NULL, size,
> -				  &waiter->bulk_waiter,
> -				  VCHIQ_BULK_MODE_BLOCKING, dir);
> +	ret = vchiq_bulk_xfer_blocking_interruptible(instance, handle, data, NULL, size,
> +						     &waiter->bulk_waiter, dir);
>   	if ((ret != -EAGAIN) || fatal_signal_pending(current) || !waiter->bulk_waiter.bulk) {
>   		struct vchiq_bulk *bulk = waiter->bulk_waiter.bulk;
>
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
> index f36044bab194..43f951fa4b89 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
> @@ -2985,6 +2985,42 @@ vchiq_remove_service(struct vchiq_instance *instance, unsigned int handle)
>   	return status;
>   }
>
> +int
> +vchiq_bulk_xfer_blocking_interruptible(struct vchiq_instance *instance, unsigned int handle,
> +				       void *offset, void __user *uoffset, int size,
> +				       void __user *userdata, enum vchiq_bulk_dir dir)
> +{
> +	struct vchiq_service *service = find_service_by_handle(instance, handle);
> +	struct bulk_waiter *bulk_waiter;
> +	enum vchiq_bulk_mode mode = VCHIQ_BULK_MODE_BLOCKING;
> +	int status = -EINVAL;
> +
> +	if (!service)
> +		return -EINVAL;
> +
> +	if (service->srvstate != VCHIQ_SRVSTATE_OPEN)
> +		goto error_exit;
> +
> +	if (!offset && !uoffset)
> +		goto error_exit;
> +
> +	if (vchiq_check_service(service))
> +		goto error_exit;
> +
> +	bulk_waiter = userdata;
> +	init_completion(&bulk_waiter->event);
> +	bulk_waiter->actual = 0;
> +	bulk_waiter->bulk = NULL;
> +
> +	status = vchiq_bulk_xfer_queue_msg_interruptible(service, offset, uoffset, size,
> +							 userdata, mode, dir);
> +
> +error_exit:
> +	vchiq_service_put(service);
> +
> +	return status;
> +}
> +
>   /*
>    * This function may be called by kernel threads or user threads.
>    * User threads may receive -EAGAIN to indicate that a signal has been
> @@ -3018,12 +3054,6 @@ int vchiq_bulk_transfer(struct vchiq_instance *instance, unsigned int handle,
>   	case VCHIQ_BULK_MODE_NOCALLBACK:
>   	case VCHIQ_BULK_MODE_CALLBACK:
>   		break;
> -	case VCHIQ_BULK_MODE_BLOCKING:
> -		bulk_waiter = userdata;
> -		init_completion(&bulk_waiter->event);
> -		bulk_waiter->actual = 0;
> -		bulk_waiter->bulk = NULL;
> -		break;
>   	default:
>   		goto error_exit;
>   	}
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.h b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.h
> index 985d9ea3a06a..2dd89101c1c6 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.h
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.h
> @@ -474,6 +474,11 @@ extern int
>   vchiq_bulk_xfer_waiting_interruptible(struct vchiq_instance *instance,
>   				      unsigned int handle, struct bulk_waiter *userdata);
>
> +extern int
> +vchiq_bulk_xfer_blocking_interruptible(struct vchiq_instance *instance, unsigned int handle,
> +				       void *offset, void __user *uoffset, int size,
> +				       void __user *userdata, enum vchiq_bulk_dir dir);
> +
>   extern int
>   vchiq_bulk_transfer(struct vchiq_instance *instance, unsigned int handle, void *offset,
>   		    void __user *uoffset, int size, void *userdata, enum vchiq_bulk_mode mode,
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_dev.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_dev.c
> index 550838d2863b..830633f2326b 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_dev.c
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_dev.c
> @@ -304,6 +304,12 @@ static int vchiq_irq_queue_bulk_tx_rx(struct vchiq_instance *instance,
>   		}
>
>   		userdata = &waiter->bulk_waiter;
> +
> +		status = vchiq_bulk_xfer_blocking_interruptible(instance, args->handle,
> +								NULL, args->data, args->size,
> +								userdata, dir);
> +
> +		goto bulk_transfer_handled;
>   	} else if (args->mode == VCHIQ_BULK_MODE_WAITING) {
>   		mutex_lock(&instance->bulk_waiter_list_mutex);
>   		list_for_each_entry(iter, &instance->bulk_waiter_list,